Design changes that happen early in the design process are less expensive when compared to those that take place after it is introduced into full-scale production.
The cost of the change increases with its development time.
The post -production stage changes can happen almost immediately the product is introduced into the production[4] or much later in the product lifecycle This might be due to many reasons including response to a changing market demand, uncovering of design faults that need to be corrected, the product or system not meeting stakeholder requirements, parts becoming obsolete or no longer available from suppliers, and so forth.
One of the issues in handling design changes is that they propagate or 'ripple out' from the points of initiation.
A range of approaches have been developed to help predict and manage design change ripple effects.